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staging: fbtft: add tearing signal detect

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For st7789v IC, when we need continuous full screen refresh, it is best to
wait for the tearing effect line signal to arrive to avoid screen tearing.

Signed-off-by: Carlis <zhangxuezhi1@yulong.com>
Link: https://lore.kernel.org/r/1612706517-124617-1-git-send-email-zhangxuezhi3@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Carlis 2021-02-07 22:01:57 +08:00 committed by Greg Kroah-Hartman
parent 95897fdf1f
commit fa7d3e66f6
1 changed files with 115 additions and 0 deletions
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115
drivers/staging/fbtft/fb_st7789v.c
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@ -7,9 +7,13 @@
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/module.h>
#include <video/mipi_display.h>
#include "fbtft.h"
@ -66,6 +70,62 @@ enum st7789v_command {
#define MADCTL_MX BIT(6) /* bitmask for column address order */
#define MADCTL_MY BIT(7) /* bitmask for page address order */
/* 60Hz for 16.6ms, configured as 2*16.6ms */
#define PANEL_TE_TIMEOUT_MS 33
static struct completion panel_te; /* completion for panel TE line */
static int irq_te; /* Linux IRQ for LCD TE line */
static irqreturn_t panel_te_handler(int irq, void *data)
{
complete(&panel_te);
return IRQ_HANDLED;
}
/*
* init_tearing_effect_line() - init tearing effect line.
* @par: FBTFT parameter object.
*
* Return: 0 on success, or a negative error code otherwise.
*/
static int init_tearing_effect_line(struct fbtft_par *par)
{
struct device *dev = par->info->device;
struct gpio_desc *te;
int rc, irq;
te = gpiod_get_optional(dev, "te", GPIOD_IN);
if (IS_ERR(te))
return dev_err_probe(dev, PTR_ERR(te), "Failed to request te GPIO\n");
/* if te is NULL, indicating no configuration, directly return success */
if (!te) {
irq_te = 0;
return 0;
}
irq = gpiod_to_irq(te);
/* GPIO is locked as an IRQ, we may drop the reference */
gpiod_put(te);
if (irq < 0)
return irq;
irq_te = irq;
init_completion(&panel_te);
/* The effective state is high and lasts no more than 1000 microseconds */
rc = devm_request_irq(dev, irq_te, panel_te_handler,
IRQF_TRIGGER_RISING, "TE_GPIO", par);
if (rc)
return dev_err_probe(dev, rc, "TE IRQ request failed.\n");
disable_irq_nosync(irq_te);
return 0;
}
/**
* init_display() - initialize the display controller
*
@ -82,6 +142,12 @@ enum st7789v_command {
*/
static int init_display(struct fbtft_par *par)
{
int rc;
rc = init_tearing_effect_line(par);
if (rc)
return rc;
/* turn off sleep mode */
write_reg(par, MIPI_DCS_EXIT_SLEEP_MODE);
mdelay(120);
@ -137,6 +203,10 @@ static int init_display(struct fbtft_par *par)
*/
write_reg(par, PWCTRL1, 0xA4, 0xA1);
/* TE line output is off by default when powering on */
if (irq_te)
write_reg(par, MIPI_DCS_SET_TEAR_ON, 0x00);
write_reg(par, MIPI_DCS_SET_DISPLAY_ON);
if (HSD20_IPS)
@ -145,6 +215,50 @@ static int init_display(struct fbtft_par *par)
return 0;
}
/*
* write_vmem() - write data to display.
* @par: FBTFT parameter object.
* @offset: offset from screen_buffer.
* @len: the length of data to be writte.
*
* Return: 0 on success, or a negative error code otherwise.
*/
static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
{
struct device *dev = par->info->device;
int ret;
if (irq_te) {
enable_irq(irq_te);
reinit_completion(&panel_te);
ret = wait_for_completion_timeout(&panel_te,
msecs_to_jiffies(PANEL_TE_TIMEOUT_MS));
if (ret == 0)
dev_err(dev, "wait panel TE timeout\n");
disable_irq(irq_te);
}
switch (par->pdata->display.buswidth) {
case 8:
ret = fbtft_write_vmem16_bus8(par, offset, len);
break;
case 9:
ret = fbtft_write_vmem16_bus9(par, offset, len);
break;
case 16:
ret = fbtft_write_vmem16_bus16(par, offset, len);
break;
default:
dev_err(dev, "Unsupported buswidth %d\n",
par->pdata->display.buswidth);
ret = 0;
break;
}
return ret;
}
/**
* set_var() - apply LCD properties like rotation and BGR mode
*
@ -259,6 +373,7 @@ static struct fbtft_display display = {
.gamma = HSD20_IPS_GAMMA,
.fbtftops = {
.init_display = init_display,
.write_vmem = write_vmem,
.set_var = set_var,
.set_gamma = set_gamma,
.blank = blank,